Storage and management of inventory is a critical function of many businesses, including the manufacturing, retail, and shipping industries. For efficiency purposes, it is desirable to communicate product information to a centralized inventory tracking system as the product is being removed or placed on shelves, rather than requiring a separate entry of product information at a central location after removal or placement of the product.
One conventional method for communicating product information to an inventory tracking system includes UPC bar codes that are placed on the products and portable bar code scanners that are carried by the workers manipulating the product. Portable bar code scanners are typically plugged in as an attachment to a portable electronic device such as a mobile computer device. The scanners are used to scan the codes of UPC labels or information on a variety of different items for the purpose of managing, storing, shipping, or otherwise handling such items. Such scanners use optical light signals that are passed over the UPC does to read the codes. Generally, the scanners are pointed at the UPC codes.
While UPC codes and scanners to read such codes provide a convenient system for capturing inventory information, such a system has several drawbacks. First, UPC scanners require a line-of sight to the UPC label or graphic on a package in order to read the code. This may be difficult to achieve when lining up the scanner with the UPC code. Additionally, UPC codes on products or packaging can be damaged or marked up so that reading the code becomes nearly impossible. Consequently, the use of radio frequency identification (RFID) tags has increased, and RFID tags are increasingly growing in popularity to replace the conventional UPC barcode tracking system.
When used on products as an inventory label, RFID tags can communicate data to an RFID reader somewhat similar to a UPC code. An RFID tag includes a microchip with data, an antenna, and sometimes a power source such as a battery (e.g. active RFID tag). An RFID reader also has an antenna, and the RFID reader's antenna transmits electromagnetic energy in the form of an RF beam or radio waves to the vicinity of the RFID tags. Each RFID tag that is located within the range of the RFID reader then energizes and sends identification information back to the RFID reader via RF radio signals. RFID tags, because they radiate their information as radio signals, may be read without having a line-of-sight arrangement between an RFID reader and a tag. While readers often focus their RF beam for efficiency, the RFID read does not have to be specifically pointed at a particular tag like a UPC reader does. In the inventory example, the identification information from an RFID tag may include an Electronic Product Code (EPC), which is a direct replacement for the UPC bar code. Thus, an RFID reader can scan and detect all products carrying an RFID tag within the range of the reader, and no manual scanning of each product is necessary.
Such non-directivity to the RFID scan, however, presents another issue. One drawback of current RFID reader systems is that several RFID tags will be read when they are within the range of the RFID reader. The RFID read process is not selective when a worker removes a specific product from a shelf full of products carrying RFID tags, a reading on an RFID reader will include the EPC or identification information of all the tagged products in the vicinity of the reader's RF beam, not just the selected product removed from the shelf. If the specific RFID tag on the removed product cannot be determined, then the RFID reader will not be able to communicate meaningful information to a centralized inventory system. Alternatively, when a worker is moving around and scanning inventory in a particular area, multiple reads may occur on multiple tags, even though information from only a specific tag is desired. Consequently, it is desirable to have a better control of the reading process and selectively in correctly identifying an RFID tag on a specific product or item.